I'm not sure if this should be in advance stats - perhaps it is too basic.
I'm working on a project that looks at the amount of cosmic rays coming out of a particular region of the sky in certain time intervals.
There are 13 readings taken:
When this is plotted, it looks like a downward trend - meaning the source is becoming less active - but it's difficult to say with such small statistics.
I though perhaps I should try to quantify the likelihood of getting such numbers if the source was essentially a constant source - ie the trend is just due to fluctuations.
Could someone please suggest how I might think about doing this?